JP2665768B2 - Information recording and playback method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an information recording / reproducing method for recording / reproducing predetermined information on / from an optical card based on a command from a host computer via SCSI.

[Background Art] SCSI (Small Computer System Interface) is an interface that connects a small computer manufactured by Sugart Co. of the United States and its peripheral device SASI (Small Computer System Interface).
ace) was standardized by ANSI (American National Standards Institute) X3.131-1986, and was rewritten. It handles 8-bit parallel signals, has a data transmission rate of 1.5 Mbytes / sec, and has a multi-tax system that controls up to seven simultaneously. You can do it.

The range of the interface standard specified by the ANSI is the following five points.

(1) Types of interface signals and their definitions, signal transfer timings (2) Protocols that define the operation sequence as an interface, definitions of each phase, etc. (3) Physical interface conditions such as cable specifications and connector specifications, transmission systems (4) Command system for executing various controls and data transfer of peripheral devices, command format and function of each command (5) Status byte format for informing the host computer of the command execution result, and This is the structure of sense data that informs an abnormal state in the process.

The command system in the above (4) is as follows.

SCSI commands are divided into eight types of groups.
The first byte of the CDB is an operation code. The upper 3 bits of the operation code instruct a group code, and the lower 5 bits specify a command code (code indicating a command type) for each group.

The length of the CDB is defined as follows for each group.

(1) Group 0: 6 bytes (2) Group 1: 10 bytes (3) Groups 2 to 4: Reserved (4) Group 5: 12 bytes (5) Group 6 to 7: Vendor unique The CDBs of groups 6 and 7 are commands that can be uniquely defined by SCSI devices.

In each command, the logical block address is such that fixed-length data blocks are continuously arranged on the logical unit.

FIG. 8 is a diagram showing a configuration example of a logical block in a hard disk device.

In FIG. 8, the data block of cylinder = 0 and sector = 0 is set to logical block address = 0, and the sector,
Each time the track and cylinder are increased by one, the logical block address is increased by one.

The advantage of the logical block address dressing is that the initiator (host computer) accesses the data by designating the logical block address of the first data block and the number of processing blocks, so that there is no need to be aware of the physical structure. It is. Therefore, when the above-described logical block address dressing is used, when devices having different numbers of cylinders, tracks, sectors, and the like are connected, they can be operated by the same software.

In SCSI, a logical unit number (hereinafter referred to as "LU
N ") to physical devices,
Also, it may be provided to a virtual device.

FIG. 9 is a diagram showing a general example of a SCSI system configuration.

As a logical unit, usually, a physical device such as a hard disk is often used as shown in FIG.

By the way, the above SCSI usually has eight logical units of 0 to 7, and can use the extended message to have 2048 logical units.

On the other hand, an optical card has thousands of tracks, and its information capacity is several megabytes. For this reason, when an optical card is used, the area of the optical card is used in accordance with the type of information, such as using the area A for the image information and the area B for the document information, depending on the application. When managed, the required information can be searched at high speed when reproducing it. Therefore,
In order to search at high speed, area division is necessary as described above.

[Problems to be Solved by the Invention] However, in the case of a SCSI system as shown in FIG. 10, when a read command over several hundred logical block addresses is issued from a host computer as an initiator, usually, an optical card To make efficient use of the bus, disconnect (disconnect) the SCSI bus so that other devices can use the bus. Then, until the buffer is full, the read operation is performed from the medium, the reselection operation is performed again, the optical card and the host computer are connected, and the read data is transferred to the host computer.

At the time of this disconnection (when the optical card is executing a command), if another command is sent from another host computer to the optical card, the following two processes are generally performed.

In the first process, when the host computer that has overcome the arbitration does not respond to the selection when selecting the optical card, the host computer fails the selection operation,
This is the process that does not execute the command.

In the second process, the selection is successful, contrary to the first process, but a busy status is returned to notify that the command cannot be executed.

In both the first processing and the second processing, the command cannot be executed. Apart from commands that actually require device operation, such as read commands and write commands, the format information of the optical card and other host computers want to quickly perform the next operation. Although it is necessary to know without waiting for the end of the command, there is a problem that it is impossible in the first and second processes.

According to the present invention, when a command that takes a relatively long time is issued from a host computer via SCSI and is disconnected, another host computer can know the state of the optical card and the information of the optical card when the command is disconnected. It is intended to provide a reproduction method.

[Means for Solving the Problems] The present invention is to receive an inquiry command and return information on an optical card, information on a drive, a controller and the like even while the optical card is disconnected.

[Operation] The present invention accepts an inquiry command and returns information on an optical card, information on a drive, a controller, and the like even while the optical card is disconnected, so that an inquiry from another host computer can be made. Re-command can be executed.

Embodiment First, the basic configuration of an optical card and the configuration of an optical head will be described. The same members are given the same numbers.

FIG. 3 is a plan view showing an example of an optical card used in the present invention.

FIG. 4 is an enlarged view of a portion indicated by A in FIG.

The optical card 1 has a linear tracking track 5 (5
−0, 5-1, 5-2,...) Are arranged at equal intervals. The data recording unit 4 (4-0, 4-1, 4-4) for recording information between adjacent tracking tracks.
2,...) Are provided. That is, the optical card 1
Has a data recording unit 4 in all of the space between one tracking track and an adjacent tracking track.

As shown in FIG. 4, a G mark 7 is provided between the tracking tracks 5-1 and 5-2. This G
The mark 7 is a mark for determining a reference track, and is arranged at a predetermined location on the optical card 1 by preformatting. On the extension of the data recording unit 4 where the G mark 7 exists, a medium type pattern 8 as an auxiliary data unit
Are preformatted or recorded with light spots. The medium type pattern 8 indicates the identification of the optical card 1, and records information such as a modulation / demodulation method, a data capacity per track, and the total number of tracks.

FIG. 5 is an explanatory diagram relating to a configuration of an optical head unit of the information recording / reproducing apparatus.

FIG. 6 is an explanatory diagram showing a light beam applied to the optical card 1. FIG.

 FIG. 7 is an explanatory diagram showing a configuration of the photodetector.

A light beam generated by a light source 27 such as a semiconductor laser is collimated by a collimator lens 28 and divided into three beams by a diffraction grating 30. These light beams are imaged by the objective lens 26 on the tracking tracks 5-1 and 5-2 of the optical card 1 and the data recording section 4-1 as shown in FIG. 5, for example, and the beam spots S1, S2, Form S3. Here, the optical card 1 is moved in the direction of arrow R shown in FIG. 5 by driving means (not shown), and the optical card 1 is scanned by the beam spots S1 to S3 in the direction in which the tracking track extends.

The reflected light from the beam spots S1, S2 and S3 is
Again, is reflected by the beam splitter 20, and is projected by the condenser lens system 21 to the photodetectors 22, 23, and 24, respectively. The condenser lens system 21 is an astigmatism system, and performs autofocus by a known astigmatism method. These photodetectors 22 to 24 are arranged in the arrangement shown in FIG. 7, and the photodetector 23 is divided into four parts A, B, C and D.

The prism 29 shown in FIG. 5 is a prism that converts the cross-sectional distribution of the collimated light beam emitted from the semiconductor laser from an ellipse to a circle.

 Next, an operation of recording information on the optical card 1 will be described.

For example, when information is recorded in the data recording unit 4-1,
First, the beam spots S1, S2, and S3 are irradiated on the tracking track 5-1, the data recording unit 4-1, and the tracking track 5-2, respectively. These beam spots are
By moving the optical card 1, scanning is performed in the direction of arrow F shown in FIG. The reflected light from beam spot S1 is a photodetector
22 and the reflected light from beam spot S3 is a photodetector
24, and a tracking signal is detected by a so-called three-beam method.

That is, when the beam spots S1 and S3 deviate from the tracking tracks 5-1 and 5-2, the photodetectors 22 and 24 are shifted.
The tracking signal is obtained by comparing the signals from the light receiving surfaces (tracking tracks 5-1 and 5-2). On the basis of this tracking signal, tracking means (not shown in FIG.
The beam splits S1, S2, S3 are moved in a direction perpendicular to the scanning direction (D shown in FIG.
Direction), and automatic tracking (AT) is performed.

Then, along the tracking tracks 5-1 and 5-2, the data recording unit 4-1 is formed by the beam split S2.
The recording pit 31 is recorded accurately.

Next, the response to the inquiry command in the present invention will be described.

FIG. 1 is a flowchart showing processing of an inquiry command in one embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a SCSI controller in the above embodiment.

When the information recording / reproducing apparatus into which the optical card 1 is inserted executes a command from the host computer, the operation may take a relatively long time. For example, when reading several megabytes of data, the optical card starts operating with one command, but the processing takes a considerable amount of time. In some cases, a seek operation for moving the head position may be performed. Even if this time is about several milliseconds, it can be said that the time is relatively long for a SCSI bus operating at 1.5 Mbytes / sec.

In such a case, the bus is disconnected, the bus is released, and another device can use the bus. Reselection is performed when the optical card 1 completes the command or when data transfer becomes possible again.

If an Inquiry command is issued from another host computer during disconnection, first, the interrupt 16 is transmitted from the SCSI protocol IC 12 to the MPU 13 as shown in FIG.
Enter against.

That is, the MPU 13 gives an instruction to the SPC 12 and this SPC 12
Performs the disconnection and reselection of the bus.
Also, another host computer issues an inquiry command, and the issued inquiry command controls the adapter, and the SCSI controller via the SCSI bus.
Select 32. In addition, in FIG.
Reference numeral 32 denotes a code indicating an information recording / reproducing device, and reference numeral 32 denotes a code indicating a SCSI controller.

 Next, the operation of the above embodiment will be described.

First, an optical card is inserted into the information recording / reproducing device, and the SCSI controller 32 to which the information recording / reproducing device is connected is connected.
Shifts to the command phase (S1) and receives the command. After the SCSI controller 32 receives the command, the SCSI controller 32 determines whether this command is an inquiry command.
The controller 32 confirms (S2).

If it is not an inquiry command, a busy status is returned (S7).

On the other hand, if it is an inquiry command in S2, the SCSI controller 32 shifts to the data transfer phase (S3), and the SCSI controller 32 transfers the format information of the optical card 1, the information of the drive and the controller to the host computer. (S4). After this transfer is completed, the status phase and the message phase are passed (S5, S6), and then the processing regarding the inquiry command is completed.

In this way, even when a command that takes a relatively long time is issued from the host computer and the SCSI bus to which the information recording / reproducing device in which the optical card 1 is inserted is connected is disconnected, another host can be connected. The computer can know the state of the optical card and information on the optical card.

After the process related to the inquiry command is completed, the optical card 1 continues the process related to the interrupted read command.

[Effects of the Invention] According to the present invention, when a relatively long command is issued from a host computer via SCSI and disconnected, the other host computers are informed of the state of the optical card and the information of the optical card. Has the effect of being able to know

[Brief description of the drawings]

FIG. 1 is a flowchart showing processing of an inquiry command in one embodiment of the present invention. FIG. 2 is a block diagram showing an example of a SCSI controller in the above embodiment. FIG. 3 is a schematic plan view showing an example of the optical card. FIG. 4 is a partially enlarged view of a portion A in FIG. FIG. 5 is an explanatory diagram relating to a configuration of an optical head unit of the information recording / reproducing apparatus. FIG. 6 is an explanatory view showing a light beam irradiated on the optical card. FIG. 7 is an explanatory diagram of an operation of the information recording / reproducing apparatus recording on an optical card. FIG. 8 is a diagram showing a configuration example of a logical block in a hard disk device. FIG. 9 is a configuration diagram of a general SCSI system. Figure 10 shows a SCSI with two host computers connected
It is a block diagram of a system. 1. Optical card 4-1 to 4-2 Data recording unit 5-0 to 5-2 Tracking track 12 SCSI protocol controller IC 13 MPU

Claims (1)

(57) [Claims] 1. An information recording / reproducing method in an information recording / reproducing apparatus for recording information on an optical card or reproducing information from the optical card based on a command from a host computer via a predetermined interface bus. Commands that require operations to access the optical card
When the information recording / reproducing device receives from the host computer, in order to release the interface bus,
A disconnection step of temporarily disconnecting the connection between the information recording / reproducing apparatus and the host computer; an access step of executing an access operation to the optical card in response to a received command; A command detecting step of detecting whether or not a command has been received in a state where the connection of the host has been disconnected; and when the command is received in the command detecting step, the received command is transmitted to the host which has transmitted the currently executing command. A command determining step of determining whether the command is an inquiry command received from another host computer different from the computer; and in the command determining step, the received command is an inquiry command received from another host computer. If it is determined that the command is Transmitting an information corresponding to the inquiry command, and determining that the received command is not an inquiry command, transmitting a busy signal. .